The USGS produced a series of maps folios. Each folio includes both topographic and geologic maps for each quad represented in that folio, as well as geologic reports with information on the geology and economic geology on that area. Only 227 folios were produced, so the area covered is very limited. This project includes every folio published. The complete folio is scanned, which includes the covers, text, maps and photographs. The folio titles are searchable through a Yahoo!Maps interface. All maps have been georeferenced and are converted to GIS shapefile and GoogleEarth kml files, all downloadable.